SHEDDING OF TEETH - INTRODUCTION AND HISTOLOGY

Physiologic process by which deciduous teeth are removed to allow succeeding permanent teeth to take their functional position in the oral cavity.

1. SHEDDING OF TEETH Dr. Reshma M Assistant Professor Dept of Oral and Maxillofacial Pathology

2. SHEDDING OF TEETH

3. CONTENTS Definition Factors Histology Pattern of resorption and shedding clinical significance

4. DEFINITION Physiologic Process By Which Deciduous Teeth Are Removed To Allow Succeeding Permanent Teeth To Take Their Functional Position In The Oral Cavity

5. The permanent teeth develops lingually to deciduous teeth and erupt in an Occlusal and vestibular direction. Resorption of deciduous tooth roots occurs in the lingual surface and these teeth are shed with much their pulp chambers intact.

6. FACTORS Pressure from erupting permanent successors Force of mastication

7. HISTOLOGY

8. MECHANISM OF RESORPTION Resorption Hard tissue Soft tissue

9. ODONTOCLAST Derived from monocytes of circulating blood stream Multinucleated with clear attachment zone and ruffled border Present in a cup shaped depression “ Howships’s lacunae

10. RESORBING ROOT DENTIN Ruffled border acts as proton pump adding H+ Primary lysosomes release hydrolytic enzymes Clear zone represents attachment apparatus Large vacuoles with acid phosphatase activity Secretion of neutral proteases including collagenase

11. odontoclasts Hard tissue matrix Collagen network disrupted Collagen released Disrupted collagen fibrils Uptake of crystals in vacuoles

12. RESORPTION OF SOFT TISSUE PULP Odontoclast in pulp chamber and root canals Single rooted teeth Molars Unusual feature

13. PERIODONTAL LIGAMENT Apoptosis Fibrobalsts exhibit signs of interference with normal cellular processes Cytotoxic alterations

14. PRESSURE Erupting successional teeth Growth of face and jaws Enlargement in size and strength of muscles of mastication Absence of successional tooth germ

15. Pressure from erupting tooth Root loss Decreased tooth support Not able to bear increased masticatory force exfoliation

16. Deciduous tooth Gingiva Cortical plate dense bone BODY of MANDIBLE ALVEOLAR BONE PDL Permanent tooth MANDIBULAR CENTRAL INCISORS at 2 y

17. Pattern of resorption & Shedding Pressure Developmental position & physiologic movement of successors

18. Pattern of shedding

19. Clinical significance Remnants of deciduous teeth Retained deciduous teeth Submerged deciduous teeth

20. conclusion

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